INVESTIGADORES
ZURITA Alfredo Eduardo
artículos
Título:
Late Pliocene Glyptodontinae (Xenarthra, Cingulata, Glyptodontidae) of South and North America: Morphology and paleobiogeographical implications in the GABI
Autor/es:
ZURITA, A. E; CARLINI, A. A; GILLETTE, D.; SANCHEZ, R.
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: London; Año: 2011 p. 178 - 185
ISSN:
0895-9811
Resumen:
Knowledge of the main aspects of the Great American Biotic Interchange
(GABI) concerning the glyptodontine Glyptodontidae (Xenarthra) is very scarce. A bidirectional dispersal
processwas recently proposed for this clade, with the presence of the North American genus Glyptotherium
Osborn recognized in latest Pleistocene sediments of northern South America (Venezuela and Brazil).
However, the earliest stages of this paleobiogeographical process remain poorly understood, mainly
because of the limited fossil record on this clade in late Pliocene sediments. The goals of this contribution
are: a) to present and describe the first record of a glyptodontine glyptodontid from the late Pliocene of
northern South America, tentatively assigned to a new species of Boreostemma Carlini et al. (Boreostemma?
sp. nov); and b) to analyze its paleobiogeographical implications with respect to the GABI. This new
materialwas recovered from the San Gregorio Formation (late Pliocene, prior theGABI) in northern Venezuela,
where it is represented by several osteoderms of the dorsal carapace. A comparison among the three known
late Pliocene glyptodontine glyptodontids of a) southern South America (Paraglyptodon), b) northern
South America (Boreostemma), and c) southern NorthAmerica ("Glyptotherium"), reveals a
series of shared characters between (b) and (c), not present in (a). The most important of these shared characters in (b)
and (c) are: all the osteoderms present a great development of the central figure, which is always
larger than the peripherals; the sulcus that delimits the central and peripheral figures is narrower and
shallower; and all the osteoderms present are relatively thin. This evidence suggests that the lineage of
Glyptodontinae which participated in theGABIand subsequently diversified in North America originated in northern
South America. Moreover, the evident morphological differences between these glyptodontines with
respect to the southern South American forms show a significant separation of both lineages since at
least latest Miocene-early Pliocene